Flow sensor

US5369994A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Hans Hecht · Stuttgart, DE
• Josef Kleinhans · Ludwigsburg, DE
• Rudolf Sauer · Memmingen, DE
• Eckart Reihlen · Reutlingen, DE
• Ulrich Kuhn · Renningen, DE

Key dates

• Filing date: Jul 21, 1993
• Grant date: Dec 6, 1994
• Expiry date: Jul 21, 2013

Classification

• Technology area (CPC G): Physics
• CPC primary: G01P1/006
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The invention is directed to a flow sensor having a heater, two temperature measuring sensors, a heater temperature sensor and a medium temperature sensor. A control circuit is provided which controls the overtemperature of the heater in dependence upon the temperature of the flowing medium. With this arrangement, the influence of the temperature dependency of the following on the sensor characteristic are compensated: viscosity, thermal conductance and thermal capacity of the medium. The relationship between the heater temperature and the temperature of the medium is adjusted in a slightly nonlinear manner by means of special evaluation circuits. In this way, a further improvement of the temperature compensation is obtained.